Managing Wireless Device Transmission Power

ABSTRACT

A wireless device receives configuration parameters of cells comprising at least a first cell type operating on a first frequency band; and a second cell type operating on a second frequency band. A calculated total transmit power is determined for signals comprising: a first SRS configured for transmission in a subframe of the first cell type in the cells, and a second SRS configured for transmission in the subframe of the second cell type in the cells. At least one of the first SRS or the second SRS is dropped or scaled based on a transmit power priority of the first SRS and the second SRS when the calculated total power exceeds a first value. The transmit power priority is based on whether the first SRS or the second SRS is configured for transmission on the first frequency band or the second frequency band.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/417,744, filed Jan. 27, 2017, which claims the benefit of U.S.Provisional Application No. 62/288,715, filed Jan. 29, 2016, which ishereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present disclosureare described herein with reference to the drawings.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers in a carrier group as per an aspect of anembodiment of the present disclosure.

FIG. 3 is an example diagram depicting OFDM radio resources as per anaspect of an embodiment of the present disclosure.

FIG. 4 is an example block diagram of a base station and a wirelessdevice as per an aspect of an embodiment of the present disclosure.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure.

FIG. 6 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 7 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure.

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure.

FIG. 10 is an example diagram depicting a downlink burst as per anaspect of an embodiment of the present disclosure.

FIG. 11 is an example diagram depicting a plurality of cells as per anaspect of an embodiment of the present disclosure.

FIG. 12 is an example diagram depicting a plurality of cells as per anaspect of an embodiment of the present disclosure.

FIG. 13 is an example diagram depicting a plurality of cells as per anaspect of an embodiment of the present disclosure.

FIG. 14 is an example diagram depicting a plurality of cells as per anaspect of an embodiment of the present disclosure.

FIG. 15 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure.

FIG. 16 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure.

FIG. 17 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure.

FIG. 18 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present disclosure enable operation ofcarrier aggregation. Embodiments of the technology disclosed herein maybe employed in the technical field of multicarrier communicationsystems. More particularly, the embodiments of the technology disclosedherein may relate to signal timing in a multicarrier communicationsystems.

The following Acronyms are used throughout the present disclosure:

ASIC application-specific integrated circuit

BPSK binary phase shift keying

CA carrier aggregation

CSI channel state information

CDMA code division multiple access

CSS common search space

CPLD complex programmable logic devices

CC component carrier

DL downlink

DCI downlink control information

DC dual connectivity

EPC evolved packet core

E-UTRAN evolved-universal terrestrial radio access network

FPGA field programmable gate arrays

FDD frequency division multiplexing

HDL hardware description languages

HARQ hybrid automatic repeat request

IE information element

LAA licensed assisted access

LTE long term evolution

MCG master cell group

MeNB master evolved node B

MIB master information block

MAC media access control

MAC media access control

MME mobility management entity

NAS non-access stratum

OFDM orthogonal frequency division multiplexing

PDCP packet data convergence protocol

PDU packet data unit

PHY physical

PDCCH physical downlink control channel

PHICH physical HARQ indicator channel

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

PCell primary cell

PCell primary cell

PCC primary component carrier

PSCell primary secondary cell

pTAG primary timing advance group

QAM quadrature amplitude modulation

QPSK quadrature phase shift keying

RBG Resource Block Groups

RLC radio link control

RRC radio resource control

RA random access

RB resource blocks

SCC secondary component carrier

SCell secondary cell

Scell secondary cells

SCG secondary cell group

SeNB secondary evolved node B

sTAGs secondary timing advance group

SDU service data unit

S-GW serving gateway

SRB signaling radio bearer

SC-OFDM single carrier-OFDM

SFN system frame number

SIB system information block

TAI tracking area identifier

TAT time alignment timer

TDD time division duplexing

TDMA time division multiple access

TA timing advance

TAG timing advance group

TB transport block

UL uplink

UE user equipment

VHDL VHSIC hardware description language

Example embodiments of the disclosure may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA, OFDM,TDMA, Wavelet technologies, and/or the like. Hybrid transmissionmechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed.Various modulation schemes may be applied for signal transmission in thephysical layer. Examples of modulation schemes include, but are notlimited to: phase, amplitude, code, a combination of these, and/or thelike. An example radio transmission method may implement QAM using BPSK,QPSK, 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radiotransmission may be enhanced by dynamically or semi-dynamically changingthe modulation and coding scheme depending on transmission requirementsand radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure. As illustrated inthis example, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. Forexample, arrow 101 shows a subcarrier transmitting information symbols.FIG. 1 is for illustration purposes, and a typical multicarrier OFDMsystem may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentdisclosure. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD and TDD duplexmechanisms. FIG. 2 shows an example FDD frame timing. Downlink anduplink transmissions may be organized into radio frames 201. In thisexample, the radio frame duration is 10 msec. Other frame durations, forexample, in the range of 1 to 100 msec may also be supported. In thisexample, each 10 ms radio frame 201 may be divided into ten equallysized subframes 202. Other subframe durations such as 0.5 msec, 1 msec,2 msec, and 5 msec may also be supported. Subframe(s) may consist of twoor more slots (for example, slots 206 and 207). For the example of FDD,10 subframes may be available for downlink transmission and 10 subframesmay be available for uplink transmissions in each 10 ms interval. Uplinkand downlink transmissions may be separated in the frequency domain.Slot(s) may include a plurality of OFDM symbols 203. The number of OFDMsymbols 203 in a slot 206 may depend on the cyclic prefix length andsubcarrier spacing.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present disclosure. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or RBs (in this example 6 to 100 RBs) may depend,at least in part, on the downlink transmission bandwidth 306 configuredin the cell. The smallest radio resource unit may be called a resourceelement (e.g. 301). Resource elements may be grouped into resourceblocks (e.g. 302). Resource blocks may be grouped into larger radioresources called Resource Block Groups (RBG) (e.g. 303). The transmittedsignal in slot 206 may be described by one or several resource grids ofa plurality of subcarriers and a plurality of OFDM symbols. Resourceblocks may be used to describe the mapping of certain physical channelsto resource elements. Other pre-defined groupings of physical resourceelements may be implemented in the system depending on the radiotechnology. For example, 24 subcarriers may be grouped as a radio blockfor a duration of 5 msec. In an illustrative example, a resource blockmay correspond to one slot in the time domain and 180 kHz in thefrequency domain (for 15 KHz subcarrier bandwidth and 12 subcarriers).

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure. FIG. 5A shows an example uplink physicalchannel. The baseband signal representing the physical uplink sharedchannel may perform the following processes. These functions areillustrated as examples and it is anticipated that other mechanisms maybe implemented in various embodiments. The functions may comprisescrambling, modulation of scrambled bits to generate complex-valuedsymbols, mapping of the complex-valued modulation symbols onto one orseveral transmission layers, transform precoding to generatecomplex-valued symbols, precoding of the complex-valued symbols, mappingof precoded complex-valued symbols to resource elements, generation ofcomplex-valued time-domain DFTS-OFDM/SC-FDMA signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued DFTS-OFDM/SC-FDMA baseband signal for each antenna portand/or the complex-valued PRACH baseband signal is shown in FIG. 5B.Filtering may be employed prior to transmission.

An example structure for Downlink Transmissions is shown in FIG. 5C. Thebaseband signal representing a downlink physical channel may perform thefollowing processes. These functions are illustrated as examples and itis anticipated that other mechanisms may be implemented in variousembodiments. The functions include scrambling of coded bits in each ofthe codewords to be transmitted on a physical channel; modulation ofscrambled bits to generate complex-valued modulation symbols; mapping ofthe complex-valued modulation symbols onto one or several transmissionlayers; precoding of the complex-valued modulation symbols on each layerfor transmission on the antenna ports; mapping of complex-valuedmodulation symbols for each antenna port to resource elements;generation of complex-valued time-domain OFDM signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued OFDM baseband signal for each antenna port is shown inFIG. 5D. Filtering may be employed prior to transmission.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present disclosure.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to aspects of an embodiments, transceiver(s) may be employed.A transceiver is a device that includes both a transmitter and receiver.Transceivers may be employed in devices such as wireless devices, basestations, relay nodes, and/or the like. Example embodiments for radiotechnology implemented in communication interface 402, 407 and wirelesslink 411 are illustrated are FIG. 1, FIG. 2, FIG. 3, FIG. 5, andassociated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to various aspects of an embodiment, an LTE network mayinclude a multitude of base stations, providing a user planePDCP/RLC/MAC/PHY and control plane (RRC) protocol terminations towardsthe wireless device. The base station(s) may be interconnected withother base station(s) (for example, interconnected employing an X2interface). Base stations may also be connected employing, for example,an S1 interface to an EPC. For example, base stations may beinterconnected to the MME employing the S1-MME interface and to the S-G)employing the S1-U interface. The S1 interface may support amany-to-many relation between MMEs/Serving Gateways and base stations. Abase station may include many sectors for example: 1, 2, 3, 4, or 6sectors. A base station may include many cells, for example, rangingfrom 1 to 50 cells or more. A cell may be categorized, for example, as aprimary cell or secondary cell. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI), and at RRCconnection re-establishment/handover, one serving cell may provide thesecurity input. This cell may be referred to as the Primary Cell(PCell). In the downlink, the carrier corresponding to the PCell may bethe Downlink Primary Component Carrier (DL PCC), while in the uplink,the carrier corresponding to the PCell may be the Uplink PrimaryComponent Carrier (UL PCC). Depending on wireless device capabilities,Secondary Cells (SCells) may be configured to form together with thePCell a set of serving cells. In the downlink, the carrier correspondingto an SCell may be a Downlink Secondary Component Carrier (DL SCC),while in the uplink, it may be an Uplink Secondary Component Carrier (ULSCC). An SCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or Cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context it is used). In the specification, cell ID maybe equally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, when thespecification refers to a first physical cell ID for a first downlinkcarrier, the specification may mean the first physical cell ID is for acell comprising the first downlink carrier. The same concept may apply,for example, to carrier activation. When the specification indicatesthat a first carrier is activated, the specification may also mean thatthe cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, variousexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices may support multiple technologies, and/or multiple releases ofthe same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE release with agiven capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of wireless devices in a coveragearea that may not comply with the disclosed methods, for example,because those wireless devices perform based on older releases of LTEtechnology.

FIG. 6 and FIG. 7 are example diagrams for protocol structure with CAand DC as per an aspect of an embodiment of the present disclosure.E-UTRAN may support Dual Connectivity (DC) operation whereby a multipleRX/TX UE in RRC_CONNECTED may be configured to utilize radio resourcesprovided by two schedulers located in two eNBs connected via a non-idealbackhaul over the X2 interface. eNBs involved in DC for a certain UE mayassume two different roles: an eNB may either act as an MeNB or as anSeNB. In DC a UE may be connected to one MeNB and one SeNB. Mechanismsimplemented in DC may be extended to cover more than two eNBs. FIG. 7illustrates one example structure for the UE side MAC entities when aMaster Cell Group (MCG) and a Secondary Cell Group (SCG) are configured,and it may not restrict implementation. Media Broadcast MulticastService (MBMS) reception is not shown in this figure for simplicity.

In DC, the radio protocol architecture that a particular bearer uses maydepend on how the bearer is setup. Three alternatives may exist, an MCGbearer, an SCG bearer and a split bearer as shown in FIG. 6. RRC may belocated in MeNB and SRBs may be configured as a MCG bearer type and mayuse the radio resources of the MeNB. DC may also be described as havingat least one bearer configured to use radio resources provided by theSeNB. DC may or may not be configured/implemented in example embodimentsof the disclosure.

In the case of DC, the UE may be configured with two MAC entities: oneMAC entity for MeNB, and one MAC entity for SeNB. In DC, the configuredset of serving cells for a UE may comprise two subsets: the Master CellGroup (MCG) containing the serving cells of the MeNB, and the SecondaryCell Group (SCG) containing the serving cells of the SeNB. For a SCG,one or more of the following may be applied. At least one cell in theSCG may have a configured UL CC and one of them, named PSCell (or PCellof SCG, or sometimes called PCell), may be configured with PUCCHresources. When the SCG is configured, there may be at least one SCGbearer or one Split bearer. Upon detection of a physical layer problemor a random access problem on a PSCell, or the maximum number of RLCretransmissions has been reached associated with the SCG, or upondetection of an access problem on a PSCell during a SCG addition or aSCG change: a RRC connection re-establishment procedure may not betriggered, UL transmissions towards cells of the SCG may be stopped, anda MeNB may be informed by the UE of a SCG failure type. For splitbearer, the DL data transfer over the MeNB may be maintained. The RLC AMbearer may be configured for the split bearer. Like a PCell, a PSCellmay not be de-activated. A PSCell may be changed with a SCG change (forexample, with a security key change and a RACH procedure), and/orneither a direct bearer type change between a Split bearer and a SCGbearer nor simultaneous configuration of a SCG and a Split bearer may besupported.

With respect to the interaction between a MeNB and a SeNB, one or moreof the following principles may be applied. The MeNB may maintain theRRM measurement configuration of the UE and may, (for example, based onreceived measurement reports or traffic conditions or bearer types),decide to ask a SeNB to provide additional resources (serving cells) fora UE. Upon receiving a request from the MeNB, a SeNB may create acontainer that may result in the configuration of additional servingcells for the UE (or decide that it has no resource available to do so).For UE capability coordination, the MeNB may provide (part of) the ASconfiguration and the UE capabilities to the SeNB. The MeNB and the SeNBmay exchange information about a UE configuration by employing RRCcontainers (inter-node messages) carried in X2 messages. The SeNB mayinitiate a reconfiguration of its existing serving cells (for example, aPUCCH towards the SeNB). The SeNB may decide which cell is the PSCellwithin the SCG. The MeNB may not change the content of the RRCconfiguration provided by the SeNB. In the case of a SCG addition and aSCG SCell addition, the MeNB may provide the latest measurement resultsfor the SCG cell(s). Both a MeNB and a SeNB may know the SFN andsubframe offset of each other by OAM, (for example, for the purpose ofDRX alignment and identification of a measurement gap). In an example,when adding a new SCG SCell, dedicated RRC signaling may be used forsending required system information of the cell as for CA, except forthe SFN acquired from a MIB of the PSCell of a SCG.

In an example, serving cells may be grouped in a TA group (TAG). Servingcells in one TAG may use the same timing reference. For a given TAG,user equipment (UE) may use at least one downlink carrier as a timingreference. For a given TAG, a UE may synchronize uplink subframe andframe transmission timing of uplink carriers belonging to the same TAG.In an example, serving cells having an uplink to which the same TAapplies may correspond to serving cells hosted by the same receiver. AUE supporting multiple TAs may support two or more TA groups. One TAgroup may contain the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not contain thePCell and may be called a secondary TAG (sTAG). In an example, carrierswithin the same TA group may use the same TA value and/or the sametiming reference. When DC is configured, cells belonging to a cell group(MCG or SCG) may be grouped into multiple TAGs including a pTAG and oneor more sTAGs.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure. In Example 1, pTAG comprises aPCell, and an sTAG comprises SCell1. In Example 2, a pTAG comprises aPCell and SCell1, and an sTAG comprises SCell2 and SCell3. In Example 3,pTAG comprises PCell and SCell1, and an sTAG1 includes SCell2 andSCell3, and sTAG2 comprises SCell4. Up to four TAGs may be supported ina cell group (MCG or SCG) and other example TAG configurations may alsobe provided. In various examples in this disclosure, example mechanismsare described for a pTAG and an sTAG. Some of the example mechanisms maybe applied to configurations with multiple sTAGs.

In an example, an eNB may initiate an RA procedure via a PDCCH order foran activated SCell. This PDCCH order may be sent on a scheduling cell ofthis SCell. When cross carrier scheduling is configured for a cell, thescheduling cell may be different than the cell that is employed forpreamble transmission, and the PDCCH order may include an SCell index.At least a non-contention based RA procedure may be supported forSCell(s) assigned to sTAG(s).

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure. An eNB transmits an activation command 600 to activate anSCell. A preamble 602 (Msg1) may be sent by a UE in response to a PDCCHorder 601 on an SCell belonging to an sTAG. In an example embodiment,preamble transmission for SCells may be controlled by the network usingPDCCH format 1A. Msg2 message 603 (RAR: random access response) inresponse to the preamble transmission on the SCell may be addressed toRA-RNTI in a PCell common search space (CSS). Uplink packets 604 may betransmitted on the SCell in which the preamble was transmitted.

According to an embodiment, initial timing alignment may be achievedthrough a random access procedure. This may involve a UE transmitting arandom access preamble and an eNB responding with an initial TA commandNTA (amount of timing advance) within a random access response window.The start of the random access preamble may be aligned with the start ofa corresponding uplink subframe at the UE assuming NTA=0. The eNB mayestimate the uplink timing from the random access preamble transmittedby the UE. The TA command may be derived by the eNB based on theestimation of the difference between the desired UL timing and theactual UL timing. The UE may determine the initial uplink transmissiontiming relative to the corresponding downlink of the sTAG on which thepreamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. According to variousaspects of an embodiment, when an eNB performs an SCell additionconfiguration, the related TAG configuration may be configured for theSCell. In an example embodiment, an eNB may modify the TAG configurationof an SCell by removing (releasing) the SCell and adding(configuring) anew SCell (with the same physical cell ID and frequency) with an updatedTAG ID. The new SCell with the updated TAG ID may initially be inactivesubsequent to being assigned the updated TAG ID. The eNB may activatethe updated new SCell and start scheduling packets on the activatedSCell. In an example implementation, it may not be possible to changethe TAG associated with an SCell, but rather, the SCell may need to beremoved and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, (for example, at least one RRC reconfigurationmessage), may be send to the UE to reconfigure TAG configurations byreleasing the SCell and then configuring the SCell as a part of thepTAG. When an SCell is added/configured without a TAG index, the SCellmay be explicitly assigned to the pTAG. The PCell may not change its TAgroup and may be a member of the pTAG.

The purpose of an RRC connection reconfiguration procedure may be tomodify an RRC connection, (for example, to establish, modify and/orrelease RBs, to perform handover, to setup, modify, and/or releasemeasurements, to add, modify, and/or release SCells). If the receivedRRC Connection Reconfiguration message includes the sCellToReleaseList,the UE may perform an SCell release. If the received RRC ConnectionReconfiguration message includes the sCellToAddModList, the UE mayperform SCell additions or modification.

In LTE Release-10 and Release-11 CA, a PUCCH may only be transmitted onthe PCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE maytransmit PUCCH information on one cell (PCell or PSCell) to a given eNB.

As the number of CA capable UEs and also the number of aggregatedcarriers increase, the number of PUCCHs and also the PUCCH payload sizemay increase. Accommodating the PUCCH transmissions on the PCell maylead to a high PUCCH load on the PCell. A PUCCH on an SCell may beintroduced to offload the PUCCH resource from the PCell. More than onePUCCH may be configured for example, a PUCCH on a PCell and anotherPUCCH on an SCell. In the example embodiments, one, two or more cellsmay be configured with PUCCH resources for transmitting CSI/ACK/NACK toa base station. Cells may be grouped into multiple PUCCH groups, and oneor more cell within a group may be configured with a PUCCH. In anexample configuration, one SCell may belong to one PUCCH group. SCellswith a configured PUCCH transmitted to a base station may be called aPUCCH SCell, and a cell group with a common PUCCH resource transmittedto the same base station may be called a PUCCH group.

In an example embodiment, a MAC entity may have a configurable timertimeAlignmentTimer per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned. The MAC entity may, when aTiming Advance Command MAC control element is received, apply the TimingAdvance Command for the indicated TAG; start or restart thetimeAlignmentTimer associated with the indicated TAG. The MAC entitymay, when a Timing Advance Command is received in a Random AccessResponse message for a serving cell belonging to a TAG and/orif theRandom Access Preamble was not selected by the MAC entity, apply theTiming Advance Command for this TAG and start or restart thetimeAlignmentTimer associated with this TAG. Otherwise, if thetimeAlignmentTimer associated with this TAG is not running, the TimingAdvance Command for this TAG may be applied and the timeAlignmentTimerassociated with this TAG started. When the contention resolution isconsidered not successful, a timeAlignmentTimer associated with this TAGmay be stopped. Otherwise, the MAC entity may ignore the received TimingAdvance Command.

In example embodiments, a timer is running once it is started, until itis stopped or until it expires; otherwise it may not be running. A timercan be started if it is not running or restarted if it is running. Forexample, a timer may be started or restarted from its initial value.

Example embodiments of the disclosure may enable operation ofmulti-carrier communications. Other example embodiments may comprise anon-transitory tangible computer readable media comprising instructionsexecutable by one or more processors to cause operation of multi-carriercommunications. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to enable operation ofmulti-carrier communications. The device may include processors, memory,interfaces, and/or the like. Other example embodiments may comprisecommunication networks comprising devices such as base stations,wireless devices (or user equipment: UE), servers, switches, antennas,and/or the like.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing and each user/device accesses an increasing number andvariety of services, e.g. video delivery, large files, images. This mayrequire not only high capacity in the network, but also provisioningvery high data rates to meet customers' expectations on interactivityand responsiveness. More spectrum may therefore needed for cellularoperators to meet the increasing demand. Considering user expectationsof high data rates along with seamless mobility, it may be beneficialthat more spectrum be made available for deploying macro cells as wellas small cells for cellular systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, may be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA may offer an alternative for operators to make use ofunlicensed spectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAmay utilize at least energy detection to determine the presence orabsence of other signals on a channel in order to determine if a channelis occupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be enabled. Someof these functions may be supported by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be supported by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission(including cell identification) by UEs, time & frequency synchronizationof UEs, and/or the like.

In an example embodiment, a DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions can start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

An LBT procedure may be employed for fair and friendly coexistence ofLAA with other operators and technologies operating in an unlicensedspectrum. LBT procedures on a node attempting to transmit on a carrierin an unlicensed spectrum may require the node to perform a clearchannel assessment to determine if the channel is free for use. An LBTprocedure may involve at least energy detection to determine if thechannel is being used. For example, regulatory requirements in someregions, for example, in Europe, may specify an energy detectionthreshold such that if a node receives energy greater than thisthreshold, the node assumes that the channel is not free. While nodesmay follow such regulatory requirements, a node may optionally use alower threshold for energy detection than that specified by regulatoryrequirements. In an example, LAA may employ a mechanism to adaptivelychange the energy detection threshold. For example, LAA may employ amechanism to adaptively lower the energy detection threshold from anupper bound. Adaptation mechanism(s) may not preclude static orsemi-static setting of the threshold. In an example a Category 4 LBTmechanism or other type of LBT mechanisms may be implemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies, no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (for example, LBT withoutrandom back-off) may be implemented. The duration of time that thechannel is sensed to be idle before the transmitting entity transmitsmay be deterministic. In an example, Category 3 (for example, LBT withrandom back-off with a contention window of fixed size) may beimplemented. The LBT procedure may have the following procedure as oneof its components. The transmitting entity may draw a random number Nwithin a contention window. The size of the contention window may bespecified by the minimum and maximum value of N. The size of thecontention window may be fixed. The random number N may be employed inthe LBT procedure to determine the duration of time that the channel issensed to be idle before the transmitting entity transmits on thechannel. In an example, Category 4 (for example, LBT with randomback-off with a contention window of variable size) may be implemented.The transmitting entity may draw a random number N within a contentionwindow. The size of the contention window may be specified by a minimumand maximum value of N. The transmitting entity may vary the size of thecontention window when drawing the random number N. The random number Nmay be employed in the LBT procedure to determine the duration of timethat the channel is sensed to be idle before the transmitting entitytransmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (for example, by using different LBT mechanismsor parameters), since the LAA UL may be based on scheduled access whichaffects a UE's channel contention opportunities. Other considerationsmotivating a different UL LBT scheme include, but are not limited to,multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. A UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, a UL transmission burst may be defined from a UEperspective. In an example, a UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

In an example embodiment, in an unlicensed cell, a downlink burst may bestarted in a subframe. When an eNB accesses the channel, the eNB maytransmit for a duration of one or more subframes. The duration maydepend on a maximum configured burst duration in an eNB, the dataavailable for transmission, and/or eNB scheduling algorithm. FIG. 10shows an example downlink burst in an unlicensed (e.g. licensed assistedaccess) cell. The maximum configured burst duration in the exampleembodiment may be configured in the eNB. An eNB may transmit the maximumconfigured burst duration to a UE employing an RRC configurationmessage.

The wireless device may receive from a base station at least one message(for example, an RRC) comprising configuration parameters of a pluralityof cells. The plurality of cells may comprise at least one license celland at least one unlicensed (for example, an LAA cell). Theconfiguration parameters of a cell may, for example, compriseconfiguration parameters for physical channels, (for example, a ePDCCH,PDSCH, PUSCH, PUCCH and/or the like).

The latest standard documents 3GPP TS 36.211, 36.212, 36.212, 36.302 and36.331 of V13.0 describe SRS processes. According to release 13 of theLTE standard, 3GPP TS 36.213, a UE may drop a sounding reference signal(SRS) transmission in many scenarios when an SRS transmission overlapswith the transmission of a PUCCH, a PUSCH, and/or a PRACH. SRS droppingwhen multiple TAGs in a CG are not configured may be higher sinceparallel transmission of SRS with PUSCH, PUCCH, PRACH in a CG may not beallowed.

The limitations in Release-13 may cause excessive dropping of SRSsignals in the uplink, especially when a number of carriers areconfigured and activated, when uplink traffic is high, and/or more thanone PUCCH is configured. For example, when PUCCH CGs are configured,PUCCH may be configured on PCell, and one or more SCells fortransmission of control information to a given eNB. This may increasethe possibility of overlapping PUCCH and SRS transmission that mayresult in increased SRS dropping. When a number of uplink channels areconfigured, and when uplink traffic is high, the possibility ofoverlapping transmission of SRS and PUSCH transport blocks may increase.This may result in increased SRS dropping.

Increased SRS dropping may also be observed when LAA cells are deployed.In an example embodiment, one or more LAA cells may be configured and/oractivated. SRS signal transmission on LAA cells may collide withinterference due to presence of other transmitters and/or hidden nodes.In an example embodiment, SRS transmission may be dropped due to LBT, ifLBT is required for SRS transmission. In an example embodiment, SRStransmission may be dropped when no UL burst including PUSCH istransmitted. There is a need to enhance SRS transmission processes andreduce the probability of SRS dropping.

SRS signals may be transmitted by the UE, and may provide a base stationwith information about channel conditions. Reducing the droppingpossibility of SRS signals in the uplink may enhance a base station'sability to estimate radio channel conditions. In an example scenario,the base station may need to transmit, in parallel, a combination of oneor more of the following signals: a PRACH signal, a PUCCH signal, PUSCHsignal(s), and SRS signal(s). The implementation of mechanisms employingparallel transmission of SRS and/or PRACH signals with other uplinkphysical channel signals may enhance network performance.

Example embodiments enhance the existing LTE Release-13 SRS transmissionprocess, when features such as uplink LAA and/or other radio interfaceenhancements are introduced in release 14. The enhanced SRS transmissionembodiments may be implemented to reduce the SRS dropping probability.Release 13 or prior wireless devices may follow their own implementationstandard, and newer devices compatible to release 14 and/or higher mayemploy the enhanced SRS mechanisms. In an example, a release 13 wirelessdevice may be configured with downlink-only LAA cells. A UE configuredwith LAA cells for downlink only transmission with no configured uplinkmay implement legacy SRS transmission procedures.

In an example embodiment, enhanced SRS transmissions are implementedwhen a UE is capable of transmission of UL LAA technology. A UE maytransmit an RRC capability message comprising one or more parametersindicating that the UE is capable of UL configuration for an LAA cell.When the UE capability message includes UL LAA configuration and signaltransmission capability, it may imply that the UE is capable of enhancedSRS transmission capability disclosed in example embodiments of theinvention. The capability message may include for example certain bandcombination or certain transmission capability that implies the UE iscapable of implementing enhanced SRS mechanisms.

In an example embodiment, enhanced SRS transmission is implemented whena UE is capable of a specific feature, e.g. enhanced-SRS feature,release 14 feature, LAA band capable. A UE may transmit an RRCcapability message comprising one or more parameters indicating a firstcapability in the UE. The first capability may (explicitly orimplicitly) imply that the UE is capable enhanced SRS mechanism. Forexample, when the UE capability message includes certain uplinktransmission capability, it may imply that the UE is capable of enhancedSRS transmission capability disclosed in example embodiments of theinvention.

In an example embodiment, when a UE is capable of a specific feature,e.g. enhanced-SRS feature, release 14 feature, LAA band capable, and/orLAA uplink carrier configuration, then enhanced SRS transmission may beimplemented when the feature is actually configured in the UE. Forexample, a UE may be capable of UL LAA, then the enhanced SRS mechanismis implemented when the UE is capable of UL LAA and eNB configures atleast one LAA carrier with uplink capability, or when the UE is capableof UL LAA and eNB configures at least one LAA carrier with uplinkcapability and SRS configuration. A UE may transmit an RRC capabilitymessage comprising one or more parameters indicating a first capabilityin the UE. The first capability may explicitly or implicitly imply thatthe UE is capable of enhanced SRS mechanism, when a first RRCconfiguration is configured in the wireless device by the eNB. Forexample, when the UE capability message includes UL LAA capability andwhen the eNB configures a cell with UL LAA transmission, it may implythat the UE is capable of enhanced SRS transmission capability disclosedin example embodiments of the invention. In an example, a UE mayimplement an example embodiment for enhanced SRS transmission when atleast one an LAA cell with uplink is configured. In an example, a UE mayimplement an example embodiment for enhanced SRS transmission when atleast one an LAA cell with uplink is configured and is activated.

In an example embodiment, an eNB may transmit at least one RRC messageconfiguring RRC and may implicitly or explicitly configure the enhancedSRS mechanism. For example, the RRC message may include one or moreparameters indicating that the enhanced SRS transmission is configuredin the wireless device. For example, an SRS dedicated configurationparameter for the UE may configure the enhanced SRS mechanism in the UE.In another example embodiment, RRC message may not need to configure theenhanced SRS mechanism, and the UE may perform an enhanced SRS mechanismwhen it is configured with certain configuration or when the UE iscompatible with certain features or certain releases of LTE advanced.

In an example embodiment, the enhanced SRS mechanism may be implementedin LAA cells with configured UL. SRSs are expected to be dropped in anLAA cell e.g. due to interference nature of the LAA cell. The enhancedSRS mechanism reduces SRS dropping probability in LAA cells. A UE may beconfigured for SRS transmission in an LAA cell in a subframe when PUSCHis transmitted in the subframe. SRS may be transmitted in the lastsymbol of a subframe, when SRS type 0 or 1 is configured fortransmission in the subframe. SRS transmission in a subframe of a cellwithout PUSCH transmission in the subframe of the cell may be supported.In an example embodiment, and depending on the UEimplementation/configuration SRS may be transmitted without LBT. Theimplementation may depend on the regulatory requirements and/or UEconfiguration/implementation for SRS transmission in an unlicensed band.

In Release-13, for example, a UE not configured with multiple TAGs shallnot transmit SRS in a symbol whenever SRS and PUSCH transmissions happento overlap in the same symbol in the same CG (MCG or SCG). Suchmechanism may increase SRS dropping probability. When multiple TAGs areconfigured, parallel transmission of SRS in a cell with transmission ofother signals (PUSCH/PUCCH/PRACH) in another cell may be allowed andconfigured. Example embodiments are implemented in a cell group (e.g. CGand/or PUCCH group) when multiple TAGs are not configured in the cellgroup. Uplink transmissions in multiple cells employing enhanced SRStransmissions belong to the same timing advance cell group and areuplink time aligned.

In an example embodiment, the enhanced SRS mechanism may be implementedin licensed cells with configured UL SRS transmission. The enhanced SRSmechanism may reduce SRS dropping probability in the cells. Enhanced SRSmechanism may be implemented in unlicensed (e.g. LAA) cells, in licensedcells, or in both licensed and unlicensed (e.g. LAA) cells depending onimplementation.

When enhanced SRS transmission mechanism is configured in a UE, SRS maybe transmitted in a first cell in parallel with PUSCH transmission inanother cell in the same cell group, even when multiple TAGs are notconfigured. In an example, enhanced SRS transmission is implemented forcells of the same CG and the same TAG.

In the current LTE specifications, if a UE is not configured withmultiple TAGs and the UE is not configured with the parametersrs-UpPtsAdd for trigger type 1, the UE does not transmit SRS in asymbol when SRS transmission and PUSCH transmissions overlaps in thesame symbol. Similar SRS behavior is supported if a UE is not configuredwith multiple TAGs and the UE is not configured with more than oneserving cell of different CPs. If the UE is not configured with multipleTAGs, then the UE drops a configured SRS transmission on the LAA SCellthus creating a transmission gap. This may require the UE to perform LBTto access the channel again. The UE may lose the channel when LBTprocedure fails. In current LTE technology, when transmission of PUSCHon an LAA cell happens in parallel with a configured transmission of anSRS on a licensed cell, the SRS on the licensed cell is dropped. Thismay increase SRS dropping on a licensed cell due to PUSCH or othertraffic on an LAA cell.

In an example embodiment, an enhanced SRS mechanism may be implementedfor LAA cells, licensed cells and/or both LAA and licensed cells. Thereis a need to support SRS mechanism on LAA cells. In additional, this mayrequire an improvement in enhancing SRS dropping mechanism, otherwise,transmission of SRS in LAA cells may have a negative impact on othercells and increase SRS dropping in the system. The enhanced SRSmechanisms introduced in example embodiments provide a mechanism fortransmission of SRS on LAA cells, licensed cells, and/or both licensedand LAA cells. The enhanced SRS mechanisms introduced in exampleembodiments provide a mechanism to reduce SRS dropping probability inthe system. Example embodiments for SRS procedure in a subframe areimplemented when the wireless device is not power limited in the uplink.When the wireless device is power limited, a configured SRS transmissionmay be dropped depending on transceiver criteria and uplink transmissionimplementation to maintain a total transmit power below an allowedtransmission power.

The wireless device may receive from a base station at least one messagecomprising configuration parameters of a plurality of cells, theplurality of cells comprising at least two cell types. The two celltypes comprising a licensed cell type and an unlicensed (e.g. licensedassisted access—LAA) cell type. The plurality of cells may comprise oneor more licensed cells and one or more unlicensed (e.g. LAA) cells. Theconfiguration parameters may comprise SRS configuration parameters.

In an example embodiment, in a given subframe, when PUSCH and/or othersignals are transmitted on the last symbol of an LAA cell, then SRS maybe transmitted on other LAA cells in parallel with PUSCH and/or othersignals on LAA cells and licensed cells. This mechanism may reduce SRSdropping in both LAA cells and licensed cells. This mechanism hasadvantages since it may reduce SRS dropping on both licensed andunlicensed cells and provide eNB with more SRSs on both licensed cellsand unlicensed cells. eNB may be able to provide more accurate uplinkchannel and timing estimation for both licensed and unlicensed cells. Inthis example embodiment, transmission of SRS on an LAA cell isindependent of parallel transmissions of other signals on a licensedcell. A sounding procedure implemented for transmission of SRS on an LAAcell may be independent of transmissions of a PUSCH and/or PUCCH in theone or more licensed cells. In an example, the sounding procedure fortransmission of SRS on an LAA cell may be independent of transmissionsof PUSCH and/or PUCCH on one or more other LAA cells or licensed cells.A sounding procedure implemented for transmission of SRS on licensedcell may be dependent on transmissions of a PUSCH and/or PUCCH in theone or more licensed cells. A sounding procedure implemented fortransmission of SRS on licensed cell may be independent of transmissionsof a PUSCH and/or PUCCH on the one or more LAA cells. For example, inFIG. 11 SRS 1 and SRS 2 may be transmitted. For example, in FIG. 12 andFIG. 13 SRS 1 may be dropped, but SRS 2 may be transmitted. In anexample embodiment, in a given subframe, when PUSCH and/or other signalsis transmitted on the last symbol a licensed cell, then SRS may betransmitted on other LAA cells in parallel with PUSCH and/or othersignals on the licensed cell. In licensed cells, SRS may be dropped whenit is scheduled for transmission with the PUSCH and/or other signals ina licensed cell. This mechanism may reduce SRS dropping in LAA cells. Inan example, parallel transmission of PUSCH and/or PUCCH on a licensedcell and SRS on an unlicensed (e.g. LAA) cell is supported. Paralleltransmission of PUSCH and/or PUCCH on an unlicensed cell and SRS onanother unlicensed cell may be supported. Parallel transmission of PUSCHand/or PUCCH on an unlicensed (e.g. LAA) cell and SRS on a licensed cellmay be supported. Parallel transmission of PUSCH and/or PUCCH on alicensed cell and SRS on another licensed cell may not be supported.

In an example embodiment, in a given subframe, when PUSCH and/or othersignals (e.g. PUCCH, reservation signal, etc) are transmitted on thelast symbol of a subframe of an LAA cell, then SRS may be transmitted onother LAA cells in parallel with PUSCH and/or other signals on LAA cell.In licensed cells, SRS may be dropped when it is scheduled fortransmission with the PUSCH and/or other signals in LAA and/or licensedcell. For example, in FIG. 11, FIG. 12, and FIG. 13 SRS 1 may bedropped, but SRS 2 may be transmitted. In this example embodiment,transmission of SRS on an LAA cell is independent of paralleltransmissions of other signals on a licensed cell. A sounding procedureimplemented for transmission of SRS on an LAA cell may be independent oftransmissions of a PUSCH and/or PUCCH in the one or more licensed cells.In an example, the sounding procedure for transmission of SRS on an LAAcell may be independent of transmissions of PUSCH and/or PUCCH on one ormore other LAA cells. A sounding procedure implemented for transmissionof SRS on a licensed cell may be dependent on transmissions of a PUSCHand/or PUCCH on the one or more licensed cells or LAA cell. Thismechanism may reduce SRS dropping in LAA cells. In an example, thesounding procedure for transmission of SRS on an LAA cell may beindependent of transmissions of PUSCH and/or PUCCH on one or more otherLAA cells or licensed cells. A sounding procedure implemented fortransmission of SRS on licensed cell may be dependent on transmissionsof a PUSCH and/or PUCCH in the one or more licensed cells or one or moreLAA cells. In an example, parallel transmission of PUSCH and/or PUCCH ona licensed cell and SRS on an unlicensed (e.g. LAA) cell is supported.Parallel transmission of PUSCH and/or PUCCH on an unlicensed cell andSRS on another unlicensed cell may be supported. Parallel transmissionof PUSCH and/or PUCCH on an unlicensed (e.g. LAA) cell and SRS on alicensed cell may not be supported. Parallel transmission of PUSCHand/or PUCCH on a licensed cell and SRS on another licensed cell may notbe supported.

In an example embodiment, in a given subframe, when PUSCH and/or othersignals is transmitted on the last symbol a licensed cell, then SRS maybe transmitted on other LAA and licensed cells in parallel with PUSCHand/or other signals on one or more licensed cells. This mechanism mayreduce SRS dropping in both LAA cells and licensed cells. This mechanismhas advantages since it may reduce SRS dropping on both licensed andunlicensed cells and provide eNB with more SRSs on both licensed cellsand unlicensed cells. eNB may be able to provide more accurate uplinkchannel and timing estimation for both licensed and unlicensed cells.This mechanism requires a change in SRS transmission in licensed cellwhen the enhanced SRS mechanism is implemented. In an exampleembodiment, in a given subframe, when PUSCH and/or other signals istransmitted on the last symbol a licensed cell and unlicensed cells,then SRS may be transmitted on other LAA and licensed cells in parallelwith PUSCH and/or other signals on licensed cells. This mechanism mayreduce SRS dropping in both LAA cells and licensed cells. This mechanismhas advantages since it may reduce SRS dropping on both licensed andunlicensed cells and provide eNB with more SRSs on both licensed cellsand unlicensed cells. eNB may be able to provide more accurate uplinkchannel and timing estimation for both licensed and unlicensed cells.This mechanism requires a change in SRS transmission in licensed cellwhen the enhanced SRS mechanism is implemented. For example, in FIG. 11,FIG. 12 and FIG. 13, SRS 1 and SRS 2 may be transmitted. In an example,the sounding procedure for transmission of SRS on an LAA cell may beindependent of transmissions of PUSCH and/or PUCCH on one or more otherLAA cells or licensed cells. A sounding procedure implemented fortransmission of SRS on licensed cell may be independent of transmissionsof a PUSCH and/or PUCCH in the one or more licensed cells or one or moreLAA cells. In this example embodiment, transmission of SRS on a cell(licensed or LAA) is independent of parallel transmissions of othersignals on another cell (licensed or LAA). In an example, paralleltransmission of PUSCH and or PUCCH on a cell (licensed or unlicensed)and SRS on another cell (licensed or unlicensed) is supported.

In an example embodiment, SRS transmission may be handled separately indifferent bands, e.g. licensed bands and unlicensed bands. In anexample, SRS transmission may be handled in a group of one or morelicensed cells independent from transmissions in a group of one or moreLAA cells and vice versa. An SRS may be transmitted in parallel withPUSCH and/or other signals in another band (e.g. licensed or LAA). AnSRS may not be transmitted in parallel with PUSCH and/or other signalsin the same band (e.g. licensed or LAA). For example, an SRS may betransmitted in an LAA cell in parallel with PUSCH and/or other signalsin a licensed cell. An SRS may be dropped in an LAA cell when it isconfigured for parallel transmission with PUSCH and/or other signals inanother LAA cell. In an example embodiment, an SRS may be transmitted ina licensed cell in parallel with PUSCH and/or other signals in an LAAcell. An SRS may be dropped in a licensed cell when it is configured forparallel transmission with PUSCH and/or other signals in anotherlicensed cell. For example, in FIG. 11, SRS 1 is transmitted and SRS 2may be dropped. For example, in FIG. 12, SRS 2 is transmitted and SRS 1may be dropped. For example, in FIG. 13, SRS 1 and SRS 2 may be dropped.In an example, the sounding procedure for transmission of SRS on an LAAcell may be independent of transmissions of PUSCH and/or PUCCH on one ormore licensed cells. In an example, the sounding procedure fortransmission of SRS on an LAA cell may be dependent on transmissions ofPUSCH and/or PUCCH on one or more LAA cells. A sounding procedureimplemented for transmission of SRS on licensed cell may be independentof transmissions of a PUSCH and/or PUCCH in or one or more LAA cells. Asounding procedure implemented for transmission of SRS on licensed cellmay be dependent on transmissions of a PUSCH and/or PUCCH in or one ormore licensed cells. In an example, parallel transmission of PUSCHand/or PUCCH on a licensed cell and SRS on an unlicensed (e.g. LAA) cellis supported. Parallel transmission of PUSCH and/or PUCCH on anunlicensed (e.g. LAA) cell and SRS on a licensed cell is supported.Parallel transmission of PUSCH and/or PUCCH on a licensed cell and SRSon another licensed cell may not be supported. Parallel transmission ofPUSCH and/or PUCCH on an unlicensed (e.g. LAA) cell and SRS on anotherunlicensed (e.g. LAA) cell may not be supported.

The SRS dropping may be reduced in the example enhanced SRS mechanismsdescribed in the specifications. Some embodiments enhance SRS mechanismin LAA cells, some in licensed cells, and some in both types of cells.

Depending on the UE implementation and/or configuration one of theenhanced SRS mechanisms or a combination of more than one embodiment maybe implemented in the wireless device. The UE implementation may reduceSRS dropping probability on licensed and/or unlicensed cells.

The embodiments of the enhanced SRS transmission may enhance UL-SCH andSRS transmission in the uplink. In the following examples, a process isdescribed for PUSCH transmission. SRS transmission may be assigned ahigher priority in some example scenarios as described below.

In an example embodiment, for the case when one transport block istransmitted in the PUSCH conveying the HARQ-ACK bits, rank indicatorbits or CRI bits:

$Q^{\prime} = {\min\left( {\left\lceil \frac{O \cdot M_{sc}^{{PUSCH}\text{-}{initial}} \cdot N_{symb}^{{PUSCH}\text{-}{initial}} \cdot \beta_{offset}^{PUSCH}}{\sum\limits_{r = 0}^{C - 1}K_{r\;}} \right\rceil,{4 \cdot M_{sc}^{PUSCH}}} \right)}$

where O is the number of HARQ-ACK bits, rank indicator bits or CRI bits,and M_(sc) ^(PUSCH) is the scheduled bandwidth for PUSCH transmission inthe current sub-frame for the transport block, expressed as a number ofsubcarriers, and N_(symb) ^(PUSCH-initial) is the number of SC-FDMAsymbols per subframe for initial PUSCH transmission for the sametransport block, respectively, given by N_(symb)^(PUSCH-initial)=(2·(N_(symb) ^(UL)−1)−N_(SRS)), where N_(SRS) is equalto 1, if UE configured with one UL cell is configured to send PUSCH andSRS in the same subframe for initial transmission, or if UE transmitsPUSCH and SRS in the same subframe in the same serving cell for initialtransmission, or if the PUSCH resource allocation for initialtransmission even partially overlaps with the cell-specific SRS subframeand bandwidth configuration, or if the subframe for initial transmissionin the same serving cell is a UE-specific type-1 SRS subframe, or if thesubframe for initial transmission in the same serving cell is aUE-specific type-0 SRS subframe and the UE is configured with multipleTAGs; or if the subframe for initial transmission in the same servingcell is a UE-specific type-0 SRS subframe and the UE is configured withenhanced SRS transmission mechanism; Otherwise N_(SRS) is equal to 0.

M_(sc) ^(PUSCH-initial), C, and K_(r) are obtained from the initialPDCCH or EPDCCH for the same transport block. If there is no initialPDCCH or EPDCCH with DCI format 0 for the same transport block, M_(sc)^(PUSCH-initial), C, and K_(r) shall be determined from: the most recentsemi-persistent scheduling assignment PDCCH or EPDCCH, when the initialPUSCH for the same transport block is semi-persistently scheduled, or,the random access response grant for the same transport block, when thePUSCH is initiated by the random access response grant.

The formula above is an example embodiment for Q′, and the exampleimplementation indicates that PUSCH transmission may consider enhancedSRS transmission mechanism for uplink transmission. For example, theexample mechanism above does not allow parallel transmission of SRS andPUSCH in the same cell. In an example embodiment, parallel transmissionof SRS and PUSCH in the same cell may be implemented. This may furtherincrease uplink transmission efficiency for PUSCH and/or SRS in theuplink. This enhance mechanism is further described in thespecification.

In an example, for each antenna port p used for transmission of thePUSCH in a subframe the block of complex-valued symbolsz^(({tilde over (p)}))(0), . . . , z^(({tilde over (p)}))(M_(symb)^(ap)−1) shall be multiplied with the amplitude scaling factor β_(PUSCH)in order to conform to the transmit power P_(PUSCH), and mapped insequence starting with z^(({tilde over (p)}))(0) to physical resourceblocks on antenna port p and assigned for transmission of PUSCH. Themapping to resource elements (k,l) corresponding to the physicalresource blocks assigned for transmission and not used for transmissionof reference signals, and not part of the last SC-FDMA symbol in asubframe, if the UE transmits SRS in the same subframe in the sameserving cell, and not part of the last SC-FDMA symbol in a subframeconfigured with cell-specific SRS, if the PUSCH transmission partly orfully overlaps with the cell-specific SRS bandwidth, and not part of anSC-FDMA symbol reserved for possible SRS transmission in a UE-specificaperiodic SRS subframe in the same serving cell, and not part of anSC-FDMA symbol reserved for possible SRS transmission in a UE-specificperiodic SRS subframe in the same serving cell when the UE is configuredwith multiple TAGs; and not part of an SC-FDMA symbol reserved forpossible SRS transmission in a UE-specific periodic SRS subframe in thesame serving cell when the UE is configured with enhanced SRStransmission mechanism.

In an example embodiment, a resource element (RE) is not employed forPUSCH transmission, if the RE is a part of an SC-FDMA symbol reservedfor possible SRS transmission in a UE-specific periodic SRS subframe inthe same serving cell when the UE is configured with enhanced SRStransmission mechanism.

SRS transmission mechanisms in release 13 and the example mechanismspresented above may not allow parallel transmission of SRS and PUSCH inthe same cell. In an example embodiment, parallel transmission of SRSand PUSCH in the same cell may be implemented in the enhanced SRSmechanism. This may further increase uplink transmission efficiency forPUSCH and/or SRS in the uplink. This enhanced mechanism is furtherdescribed in the specification.

In an example embodiment of the invention PUSCH signal transmissions maybe further optimized by allowing parallel transmission of SRS and PUSCHsignal transmission. Such configuration may be enabled when enhanced SRSconfiguration is implemented/configured.

In Release 13 and before, the mapping of PUSCH to resource elements(k,l) corresponding to the physical resource blocks assigned fortransmission may consider that resource elements (k,l) is not part ofthe last SC-FDMA symbol in a subframe, if the UE transmits SRS in thesame subframe in the same serving cell. This condition prevents paralleltransmission of SRS with PUSCH signal in a subframe, even if they arenot overlapping. This may reduce the radio resources for transmission ofPUSCH and reduce overall uplink transmission efficiency.

In an example embodiment, SRS and PUSCH may be transmitted in parallelwhen SRS and PUSCH resources are not overlapping. In an example, PUSCHand/or other signals may be transmitted in the last SC-FDMA symbol in asubframe of a cell, if the UE transmits SRS in the same subframe in thesame serving cell, and SRS is not overlapping with the transmission ofPUSCH. This may increase available resources for transmission of PUSCHand/or other uplink signal transmissions. In this example enhanced SRSmechanism, uplink radio efficiency is increased in the uplink. Anexample of parallel transmission of SRS and PUSCH is shown in Figure D.In this example, the PUSCH transmission does not partly or fullyoverlaps with the cell-specific SRS bandwidth. Such mechanism may beimplemented in only unlicensed cells, only in licensed cells, or bothlicensed and unlicensed cells.

In an example embodiment, SRS and PUSCH may be transmitted in parallelwhen SRS and PUSCH resources are overlapping. In an example, PUSCHand/or other signals may be transmitted in the last SC-FDMA symbol in asubframe of a cell, if the UE transmits SRS in the same subframe in thesame serving cell, and SRS may overlap with the resource elementsconfigured for PUSCH. This may increase available resources fortransmission of PUSCH and/or other uplink signal transmissions. In thisexample enhanced SRS mechanism, uplink radio efficiency is increased inthe uplink. An example of parallel transmission of SRS and PUSCH isshown in Figure E. In this example, the PUSCH transmission may partlyoverlap with UE-specific SRS and/or the cell-specific SRS bandwidth. Insuch a case, the resource elements that are overlapping with UE-specificSRS and/or cell-specific SRS bandwidth may not be used for PUSCH and/orother signals. The resource elements that are non-overlapping withUE-specific SRS and/or cell-specific SRS bandwidth may be used for PUSCHand/or other signals. Such mechanism may be implemented in onlyunlicensed cells, only in licensed cells, or both licensed andunlicensed cells.

Example embodiments of the inventions for enhanced SRS mechanisms areapplicable when UE is not power limited and is capable of transmittingSRS signals as calculated by UE power control formulas. Some of theexample embodiments may be combined to further enhance SRS transmissionimplementations. For example, SRS transmission in parallel with PUSCH inthe same serving cell may be combined with SRS dropping mechanismsacross different cells to further enhance the uplink efficiency.

In some cases, multiple LAA cells are activated and are aggregated atthe UE and the UE may not be capable of simultaneous reception andtransmission in the aggregated cells (a group of cells). In a givensubframe, at least one of the cells in the group may be considered theleading cell and other cells in the group may be the following cells inthe given subframe. The following constraints apply: if the subframe inthe leading cell is a downlink subframe, the UE may not transmit anysignal or channel on other cells in the group in the same subframe. Forexample, SRS signals may be dropped in other cells of the group.

In Release-13, a UE not configured with multiple TAGs shall not transmitSRS in a symbol whenever SRS and PUSCH transmissions happen to overlapin the same symbol in the same CG (MCG or SCG). Such mechanism mayincrease SRS dropping probability.

Enhanced mechanisms introduced in example embodiments of the inventionreduces SRS dropping probability. In many instances, SRS signals aretransmitted in parallel with PUSCH and/or other signals (e.g. PUCCH,reservation signals, other SRSs) in parallel in the same Cell Group (MCGand/or SCG).

In many scenarios, the UE may not have enough transmission power totransmit SRS signals and PUSCH and/or other signals in parallel.Enhanced power control mechanisms are required to enable enhanced SRStransmission mechanisms when UE is power limited.

FIG. 14 describes an example embodiment, wherein SRS signals aretransmitted in parallel with PUSCH and/or other signals and/orreservation signal. Many different combinations are possible. In anexample implementation, transmission of reservation signals (R) may notbe implemented in the UE. In another example implementation,transmission of reservation signals may be implemented in the UE.

In an example embodiments transmission powers may be assigned differenttransmission priorities. Assigning different transmission priorities todifferent signals in an enhanced SRS transmission mechanism may simplifythe power management in the UE. In an example embodiment, there may bemany implementations for handling signals with lower priorities, whenthe UE does not have enough transmission power. In one exampleembodiment, signals with lower priorities may be dropped when the UEdoes not have enough transmission power. In an example embodimentsignals with lower priorities may be adjusted (scaled down) when the UEdoes not have enough transmission power. In an example embodiment, someof the signals with lower priorities may be dropped, and some others maybe adjusted (scaled down) when the UE does not have enough transmissionpower.

For simplicity we may consider one CG in the following exampleembodiments. When DC or PUCCH CGs are configured, the UE may combine theexample embodiments in a CG along with CG power control mechanismsdisclosed in the specification.

Reservation signals are transmitted during a period that is expected tobe smaller than one subframe but may be larger than or smaller than asymbol depending on the UE implementation/configuration and many otherfactors.

In an example embodiment, SRS transmission power may be assigned a lowerpriority compared with PUCCH, and PUSCH and R signal transmissions. Inan example embodiment, there may be many implementations for handlingsignals with lower priorities, when the UE does not have enoughtransmission power. In one example embodiment, SRS may be dropped whenthe UE does not have enough transmission power. In an example embodimentSRS power may be adjusted (scaled down) when the UE does not have enoughtransmission power. In an example embodiment, some of the SRS signalswith lower priorities may be dropped, and some other SRSs may beadjusted (scaled down) if needed when the UE does not have enoughtransmission power. For example, SRS in licensed bands or unlicensedbands may be dropped. In another example, a first type of SRS may bedropped and a second type of SRS may be transmitted and/or scaled downif needed.

In an example embodiment, SRS transmission power may be assigned a lowerpriority compared with PUCCH, and PUSCH signal transmissions, but not Rsignal transmissions. R signals transmission power may be assigned alower priority compared with SRS. R signal transmission power may bescaled down or R signal may be dropped when the UE does not have enoughtransmit power.

The UE may calculate remaining power for SRS transmission according tothe defined priorities.

In an example embodiment, when the UE does not have enough power totransmit SRS and PUSCH in parallel in multiple cells, the UE may dropSRS transmissions across all the cells in a CG. This mechanism may besimple but may increase the probability of SRS dropping in the UE.

In an example embodiment, when the UE does not have enough power totransmit SRS and PUSCH in parallel in multiple cells, the UE mayconsider different priorities for SRS signals in LAA cells and licensedcells.

For example, the UE may consider higher priority for SRS transmission onLAA cells compared with licensed cells. For example, the UE may drop SRStransmissions across licensed cells in a CG. The UE may transmit SRStransmissions across LAA cells in a CG if it has sufficient power. Ifthe UE does not have sufficient power to transmit SRS on only LAA cells,then the UE also drops SRS transmission on LAA cells.

For example, the UE may consider higher priority for SRS transmission onlicensed cells compared with LAA cells. For example, the UE may drop SRStransmissions across LAA cells in a CG. The UE may transmit SRStransmissions across licensed cells in a CG if it has sufficient power.If the UE does not have sufficient power to transmit SRS on onlylicensed cells, then the UE also drops SRS transmission on licensedcells.

In an example embodiment, SRS signals that are transmitted in a subframeof a serving cell that does not include PUSCH transmission may beprioritized differently from SRS signals that are transmitted in asubframe of a serving cell that includes transmission of PUSCH. Forexample, this may allow the UE to drop if SRS is transmitted alonewithout PUSCH in the subframe, when the UE is power limited, while theUE transmits SRS in a cell with PUSCH in the subframe of the cell (if UEhas enough power). In another example, this may allow the UE to drop ifSRS is transmitted with PUSCH in the subframe, when the UE is powerlimited, while the UE transmits SRS in a cell without PUSCH in thesubframe of the cell (if UE has enough power).

In an example embodiment, SRS signals adjacent to PUSCH transmission (inthe same or subsequent subframe) may be prioritized differently from SRSsignals that are not adjacent to PUSCH. For example, this may allow theUE to drop if SRS is transmitted alone without PUSCH, when the UE ispower limited, while the UE transmits SRS adjacent with PUSCH in thecell (if UE has enough power). In another example, this may allow the UEto drop if SRS adjacent PUSCH in the subframe, when the UE is powerlimited, while the UE transmits SRS that is not adjacent to PUSCH in thecell (if UE has enough power).

In an example embodiment, a UE may consider power scaling for SRStransmission in addition to the above priorities. This may allow the UEto transmit SRSs when adjusted (scaled down) transmission power when SRStransmission at the calculated power exceeds maximum transmission power.Instead of dropping SRSs of certain category, the UE may scale down thepower of SRS transmission of a category. The lower category of SRS maystill be dropped (if there is not enough power to transmit the SRS). Insome embodiments all SRS transmissions may be considered of the samepower category and/or priority. In an example, the UE may prioritize SRStransmission powers based on whether SRS is transmitted on a licensed orunlicensed band. For example, SRS in licensed bands or unlicensed bandsmay be scaled first depending on implementation. In another example, afirst type of SRS may be scaled or dropped if needed, and a second typeof SRS may be transmitted.

In an example embodiment, the UE may drop an SRS at the end of an uplinkburst. The last symbol of the last full subframe may be dropped to allowfor LBT by other UEs.

An example embodiment provides a power control mechanism for paralleltransmission of SRS and PUSCH in the same cell. In some exampleembodiments of enhanced SRS mechanism, parallel SRS and PUSCHtransmissions in a serving cell may be implemented. SRS and PUSCH powersmay be calculated according to a power control formula and max powerlimitation in serving cell. In the example embodiment, the parallel SRStransmission with PUSCH in a serving cell may exceed the maxtransmission of the serving cell if no additional power controlmechanism is adopted.

The UE may calculate the SRS and PUSCH transmission power on a givenserving cell according to PUSCH and PUCCH power control formula. In anexample embodiment, if the total transmission power of the UE in aserving cell exceeds the maximum transmission power, the UE may drop SRStransmission in the serving cell. In an example embodiment, if the totaltransmission power of the UE in a serving cell exceeds the maximumtransmission power, the UE may scale down SRS transmission power in theserving cell so that the total transmission power is equal or below themaximum transmission power. In an example, SRS power of the serving cellmay be scaled down, in another example the same scaling factor may beapplied to a group of SRS signals.

In the power calculation, if SRS and PUSCH are transmitted and SRS andPUSCH transmission overlap in frequency, the maximum power calculationin the last symbol may consider that PUSCH is not transmitted in all theallocated symbols. The total PUSCH transmission power in the last symbolmay be less than total PUSCH transmission in other symbols of thesubframe of the serving cell, since less number of REs are employed forPUSCH in the last symbol. This may be considered in the PUSCHcalculation for the last symbol. For example, if PUSCH is transmitted in60% of the allocated REs, then 60% or subframe PUSCH is considered forthe last symbol of PUSCSH. In an example embodiment, if the totaltransmission power of the UE in a serving cell exceeds the maximumtransmission power, the UE may drop SRS transmission in the servingcell. In an example embodiment, if the total transmission power of theUE in a serving cell exceeds the maximum transmission power, the UE mayscale down SRS transmission power in the serving cell so that the totaltransmission power is equal or below the maximum transmission power. Inan example, SRS power of the serving cell may be scaled down, in anotherexample the same scaling factor may be applied to a group of SRSsignals.

Uplink power control may control the transmit power of the differentuplink physical channels. For PUSCH, the transmit power {circumflex over(P)}_(PUSCH,c)(i), may be first scaled by the ratio of the number ofantennas ports with a non-zero PUSCH transmission to the number ofconfigured antenna ports for the transmission scheme. The resultingscaled power may be split equally across the antenna ports on which thenon-zero PUSCH is transmitted.

For PUCCH or SRS, the transmit power {circumflex over (P)}_(PUSCH)(i),or {circumflex over (P)}_(SRS,c)(i) may be split equally across theconfigured antenna ports for PUCCH or SRS. {circumflex over(P)}_(SRS,c)(i) is the linear value of P_(SRS,c)(i). For a serving cellwith frame structure type 1, a UE may not be expected to be configuredwith UplinkPowerControlDedicated-v12x0.

In an example, the setting of the UE Transmit power for a PhysicalUplink Shared Channel (PUSCH) transmission may be defined as follows. Ifthe UE transmits PUSCH without a simultaneous PUCCH for the serving cellc, then the UE transmit power P_(PUSCH,c)(i) for PUSCH transmission insubframe i for the serving cell c may be given by

${P_{{PUSCH},c}(i)} = {\min \begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{{10{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\; \_ \; {PUSCH}},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + \Delta_{{TF},c} + {f_{c}(i)}}\end{Bmatrix}{\quad\lbrack{dBm}\rbrack}}$

In an example, if the UE transmits PUSCH simultaneous with PUCCH for theserving cell c, then the UE transmit power P_(PUSCH,c)(i) for the PUSCHtransmission in subframe i for the serving cell c is given by

${P_{{PUSCH},c}(i)} = {\min \begin{Bmatrix}{{10{\log_{10}\left( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)}},} \\{{10{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\; \_ \; {PUSCH}},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + \Delta_{{TF},c} + {f_{c}(i)}}\end{Bmatrix}{\quad\lbrack{dBm}\rbrack}}$

In an example, if the UE is not transmitting PUSCH for the serving cellc, for the accumulation of TPC command received with DCI format 3/3A forPUSCH, the UE may assume that the UE transmit power P_(PUSCH,c)(i) forthe PUSCH transmission in subframe i for the serving cell c is computedby P_(PUSCH,c)(i)=min{P_(CMAX,c)(i), P_(O) _(_)_(PUSCH,c)(1)+α_(c)(1·PL_(c)+f_(c)(i)} [dBm].

where, P_(CMAX,c)(i) may be the configured UE transmit power in subframei for serving cell c and {circumflex over (P)}_(CMAX,c)(i) is the linearvalue of P_(CMAX,c)(i). If the UE does not transmit PUCCH and PUSCH insubframe i for the serving cell c, for the accumulation of TPC commandreceived with DCI format 3/3A for PUSCH, the UE may computeP_(CMAX,c)(i) assuming MPR=0 dB, A-MPR=0 dB, P-MPR=0 dB and □TC=0 dB,where MPR, A-MPR, P-MPR and □TC. {circumflex over (P)}_(PUCCH)(i) may bethe linear value of P_(PUCCH)(i). M_(PUSCH,c)(i) may be the bandwidth ofthe PUSCH resource assignment expressed in number of resource blocksvalid for subframe i and serving cell c. Parameters in the power controlmechanism may be described in latest release of 3GPP TS 36.213specifications. PL_(c) may be the downlink path loss estimate calculatedin the UE for serving cell c in dB andPL_(c)=referenceSignalPower−higher layer filtered RSRP, wherereferenceSignalPower is provided by higher layers for the referenceserving cell and the higher layer filter configuration for the referenceserving cell.

In an example, δ_(PUSCH,c) may be a correction value, also referred toas a TPC command and is included in PDCCH/EPDCCH with DCI format 0/4 forserving cell c or jointly coded with other TPC commands in PDCCH withDCI format 3/3A whose CRC parity bits are scrambled with TPC-PUSCH-RNTI.If the UE is configured with higher layer parameterUplinkPowerControlDedicated-v12x0 for serving cell c and if subframe ibelongs to uplink power control subframe set 2 as indicated by thehigher layer parameter tpc-SubframeSet-r12, the current PUSCH powercontrol adjustment state for serving cell c is given by f_(c,2)(i), andthe UE may use f_(c,2)(i) instead of f_(c)(i) to determine P_(PUSCH,c).Otherwise, the current PUSCH power control adjustment state for servingcell c is given by f_(c)(i). f_(c,2) and f_(c)(i) are defined by:f_(c)(i)=f_(c)(i−1)+δ_(PUSCH,c)(i−K_(PUSCH)) andf_(c,2)(i)=f_(c,2)(i−1)+δ_(PUSCH,c)(i−K_(PUSCH)) if accumulation isenabled based on the parameter Accumulation-enabled provided by higherlayers or if the TPC command δ_(PUSCH,c) is included in a PDCCH/EPDCCHwith DCI format 0 for serving cell c where the CRC is scrambled by theTemporary C-RNTI. The value of K_(PUSCH) may be predefined.f_(c)(i)=δ_(PUSCH,c)(i−K_(PUSCH)) andf_(c,2)(i)=δ_(PUSCH,c)(i−K_(PUSCH)) if accumulation is not enabled forserving cell c based on the parameter Accumulation-enabled provided byhigher layers.

In an example, if the UE is not configured with an SCG or a PUCCH-SCell,and if the total transmit power of the UE would exceed {circumflex over(P)}_(CMAX)(i), the UE may scale {circumflex over (P)}_(PUSCH,c)(i) forthe serving cell c in subframe i such that the condition

${\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)$

is satisfied where {circumflex over (P)}_(PUCCH)(i) is the linear valueof P_(PUCCH)(i), {circumflex over (P)}_(PUSCH,c)(i) is the linear valueof P_(PUSCH,c)(i), {circumflex over (P)}_(CMAX)(i) is the linear valueof the UE total configured maximum output power P_(CMAX) in subframe iand w(i) is a scaling factor of {circumflex over (P)}_(PUSCH,c)(i) forserving cell c where 0≤w(i)≤1. In case there is no PUCCH transmission insubframe i {circumflex over (P)}_(PUCCH)(i)=0.

In an example, if the UE is not configured with an SCG or a PUCCH-Scell,and if the UE has PUSCH transmission with UCI on serving cell j andPUSCH without UCI in any of the remaining serving cells, and the totaltransmit power of the UE would exceed {circumflex over (P)}_(CMAX)(i),the UE scales {circumflex over (P)}_(PUSCH,c)(i) for the serving cellswithout UCI in subframe i such that the condition

${\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},j}(i)}} \right)$

is satisfied where {circumflex over (P)}_(PUSCH,j)(i) is the PUSCHtransmit power for the cell with UCI and w(i) is a scaling factor of{circumflex over (P)}_(PUSCH,c)(i) for serving cell c without UCI. Inthis case, no power scaling may be applied to {circumflex over(P)}_(PUSCH,j)(i) unless

${\sum\limits_{c \neq j}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} = 0$

and the total transmit power of the UE still would exceed {circumflexover (P)}_(CMAX)(i).

For a UE not configured with a SCG or a PUCCH-SCell, w(i) values may bethe same across serving cells when w(i)>0 but for certain serving cellsw(i) may be zero.

In an example, if the UE is not configured with an SCG or a PUCCH-SCell,and if the UE has simultaneous PUCCH and PUSCH transmission with UCI onserving cell j and PUSCH transmission without UCI in any of theremaining serving cells, and the total transmit power of the UE wouldexceed {circumflex over (P)}_(CMAX)(i), the UE obtains {circumflex over(P)}_(PUSCH,c)(i) according to

P̂_(PUSCH, j)(i) = min (P̂_(PUSCH, j)(i), (P̂_(CMAX)(i) − P̂_(PUCCH)(i)))${{and}\mspace{14mu} {\sum\limits_{c \neq j}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}}} \leq {\left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{\hat{P}}_{{PUSCH},j}(i)}} \right).}$

In an example, if serving cell c is the primary cell, for PUCCH format1/1a/1b/2/2a/2b/3, the setting of the UE Transmit power P_(PUCCH) forthe physical uplink control channel (PUCCH) transmission in subframe ifor serving cell c may be defined by

${P_{PUCCH}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0\; \_ \; {PUCCH}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} + {\Delta_{F\; \_ \; {PUCCH}}(F)} +} \\{{\Delta_{TxD}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

In an example, if serving cell c is the primary cell, for PUCCH format4/5, the setting of the UE Transmit power P_(PUCCH) for the physicaluplink control channel (PUCCH) transmission in subframe i for servingcell c is defined by

${P_{PUCCH}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0\; \_ \; {PUCCH}} + {PL}_{c} + {10\log_{10}\left( {M_{{PUCCH},c}(i)} \right)} + {\Delta_{{TF},c}(i)} +} \\{{\Delta_{F\; \_ \; {PUCCH}}(F)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

If the UE is not transmitting PUCCH for the primary cell, for theaccumulation of TPC command for PUCCH, the UE may assume that the UEtransmit power P_(PUCCH) for PUCCH in subframe i is computed by

P _(PUCCH)(i)=min{P _(CMAX,c)(i),P ₀ _(_) _(PUCCH) +PL _(c) +g(i)} [dBm]

In an example, the setting of the UE Transmit power P_(SRS) for the SRStransmitted on subframe i for serving cell c may be defined by

P _(SRS,c)(i)=min{P _(CMAX,c)(i),P _(SRS) _(_) _(OFFSET,c)(m)+10 log₁₀(M_(SRS,c))+P _(O) _(_) _(PUSCH,c)(j)+α_(c)(j)·PL _(c) +f _(c)(i)} [dBm]

Where P_(CMAX,c)(i) may be the configured UE transmit power in subframei for serving cell c. P_(SRS) _(_) _(OFFSET,c)(m) may be semi-staticallyconfigured by higher layers for m=0 and m=1 for serving cell c. For SRStransmission given trigger type 0 then m=0 and for SRS transmissiongiven trigger type 1 then m=¹. M_(SRS,c) may be the bandwidth of the SRStransmission in subframe i for serving cell c expressed in number ofresource blocks. f_(c)(i) may be the current PUSCH power controladjustment state for serving cell. P_(O) _(_) _(PUSCH,c)(j) and α_(c)(j)may be parameters as for subframe i, where j=1.

In an example, if the UE is not configured with an SCG or a PUCCH-SCell,and if the total transmit power of the UE for the Sounding ReferenceSymbol in an SC-FDMA symbol would exceed {circumflex over(P)}_(CMAX)(i), the UE may scale {circumflex over (P)}_(SRS,c)(i) forthe serving cell c and the SC-FDMA symbol in subframe i such that thecondition

${\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{SRS},c}(i)}}} \leq {{\hat{P}}_{CMAX}(i)}$

is satisfied where {circumflex over (P)}_(SRS,c)(i) is the linear valueof P_(SRS,c)(i), P_(CMAX)(i) is the linear value of P_(CMAX) in subframei and w(i) is a scaling factor of {circumflex over (P)}_(SRS,c)(i) forserving cell c where 0<w(i)≤1. In an example, in an enhanced SRSprocedures some of the SRS signals may be prioritized over some otherSRS signals. In an example, some of the SRS signals may be dropped orscaled according to an SRS priority mechanism in example embodiments.

In an example, if the UE is not configured with an SCG or a PUCCH-SCell,and if the UE is configured with multiple TAGs and the SRS transmissionof the UE in an SC-FDMA symbol for a serving cell in subframe i in a TAGoverlaps with the SRS transmission in another SC-FDMA symbol in subframei for a serving cell in another TAG, and if the total transmit power ofthe UE for the Sounding Reference Symbol in the overlapped portion wouldexceed {circumflex over (P)}_(CMAX)(i), the UE scales P_(SRS,c)(i) forthe serving cell c and a of the overlapped SRS SC-FDMA symbols insubframe i such that the condition

${\sum\limits_{c}{{w(i)} \cdot {{\hat{P}}_{{SRS},c}(i)}}} \leq {{\hat{P}}_{CMAX}(i)}$

is satisfied where {circumflex over (P)}_(SRS,c)(i) is the linear valueof P_(SRS,c)(i). {circumflex over (P)}_(CMAX)(i) is the linear value ofP_(CMAX) in subframe i and w(i) is a scaling factor of {circumflex over(P)}_(SRS,c)(i) for serving cell c where 0<w(i)≤1. In an example, in anenhanced SRS procedures some of the SRS signals may be prioritized oversome other SRS signals. In an example, some of the SRS signals may bedropped or scaled according to an SRS priority mechanism in exampleembodiments.

In an example, if the UE is configured with higher layer parameterUplinkPowerControlDedicated-v12x0 for serving cell c and if subframe ibelongs to uplink power control subframe set 2 as indicated by thehigher layer parameter tpc-SubframeSet-r12, the UE may use f_(c,2)(i)instead of f_(c)(i) to determine P_(SRS,c)(i) for subframe i and servingcell c.

In an example, a UE may transmit Sounding Reference Symbol (SRS) on perserving cell SRS resources based on two trigger types: trigger type 0:e.g. higher layer signalling and/or trigger type 1: e.g. DCI formats0/4/1A for FDD and TDD and DCI formats 2B/2C/2D for TDD. In case bothtrigger type 0 and trigger type 1 SRS transmissions would occur in thesame subframe in the same serving cell, the UE may only transmit thetrigger type 1 SRS transmission.

A UE may be configured with SRS parameters for trigger type 0 andtrigger type 1 on a serving cell. One or more of the following SRSparameters may be serving cell specific and semi-statically configurableby higher layers for trigger type 0 and for trigger type 1: Number ofcombs K_(TC) for trigger type 0 and a configuration of trigger type 1,if configured; Transmission comb k _(TC), for trigger type 0 and aconfiguration of trigger type 1; Starting physical resource blockassignment n_(RRC), for trigger type 0 and a configuration of triggertype 1; duration: single or indefinite (until disabled), for triggertype 0; srs-ConfigIndex ISRS for SRS periodicity T_(SRS) and SRSsubframe offset T_(offset), for trigger type 0 and SRS periodicityT_(SRS,1) and SRS subframe offset T_(offset,1) for trigger type 1; SRSbandwidth B_(SRS), for trigger type 0 and a configuration of triggertype 1; Frequency hopping bandwidth, b_(hop) for trigger type 0; Cyclicshift n_(SRS) ^(cs), for trigger type 0 and a configuration of triggertype 1; and Number of antenna ports N_(p) for trigger type 0 and aconfiguration of trigger type 1.

According to various embodiments, the wireless device may comprise oneor more processors and memory. The memory may store instructions that,when executed by the one or more processors, cause the wireless deviceto perform a series of actions. Embodiments of example actions areillustrated in the accompanying figures and specification.

FIG. 15 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. A wireless device may receive at least onemessage at 1510. The at least one message may comprise configurationparameters of a plurality of cells. The plurality of cells may compriseone or more licensed cells and one or more licensed assisted access(LAA) cells. According to an embodiment, the plurality of cells may bein a same timing advance group (TAG). According to an embodiment, theplurality of cells may be in a same cell group and in a same physicaluplink control channel (PUCCH) group. According to an embodiment, the atleast one message may comprise SRS configuration parameters. The SRSconfiguration parameters comprise an SRS bandwidth parameter and an SRSsubframe configuration parameter.

At least one sounding reference signal (SRS) may be transmitted at 1520.The transmission may be in a subframe on an LAA cell of the one or moreLAA cells. The transmission may employ a sounding procedure for the oneor more LAA cells. The sounding procedure may be independent oftransmissions of a physical uplink shared channel (PUSCH) in the one ormore licensed cells. The sounding procedure may comprise, for example, afirst procedure for transmitting the at least one SRS and a secondprocedure for dropping configured transmissions of at least one secondSRS. The transmitting of the at least one SRS may be, for example, inresponse to receiving downlink control information from a base station.

According to an embodiment, the wireless device may not be uplink powerlimited during the subframe. The wireless device may further transmit amessage to a base station. The message may comprise one or moreparameters. The one or more parameters may indicate that the wirelessdevice supports an enhanced SRS transmission procedure. According to anembodiment, the one or more parameters may indicate that the wirelessdevice supports configuration of an uplink for an unlicensed cell.

FIG. 16 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. A wireless device may receive at least onemessage at 1610. The at least one message may comprise configurationparameters of a plurality of cells. The plurality of cells may compriseone or more licensed cells and one or more licensed assisted access(LAA) cells. According to an embodiment, the plurality of cells may bein a same timing advance group (TAG).

At 1620, the wireless device may transmit, in a subframe on a licensedcell of the one or more licensed cells, at least one SRS. The at leastone SRS may employ a sounding procedure for the one or more licensedcells. The sounding procedure may be independent of transmissions of aphysical uplink shared channel (PUSCH) in the one or more LAA cells.According to an embodiment, the sounding procedure may comprise a firstprocedure for transmitting the at least one SRS and a second procedurefor dropping configured transmissions of at least one second SRS.According to an embodiment, the at least one message may comprise SRSconfiguration parameters comprising an SRS bandwidth parameter and anSRS subframe configuration parameter. The wireless device may transmitthe at least one SRS in response to receiving downlink controlinformation from a base station.

The wireless device may, for example, not be uplink power limited duringthe subframe. According to an embodiment, the wireless device, mayfurther transmit to a base station a message comprising one or moreparameters. The one or more parameters may indicate, for example, thatthe wireless device supports an enhanced SRS transmission procedure. Theone or more parameters may indicate, for example, that the wirelessdevice supports configuration of an uplink for an unlicensed cell.

FIG. 17 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1710, a wireless device may receive at leastone message comprising configuration parameters of a plurality of cells.The plurality of cells may comprise at least two cell types. The atleast two two cell types comprising a licensed cell type and a licensedassisted access (LAA) cell type.

A calculated total transmit power may be determined at 1720 for aplurality of signals. The plurality of signals may comprise a first SRSand a second SRS. The first SRS may be configured for transmission in asubframe of the LAA cell type in the plurality of cells. The second SRSmay be configured for transmission in the subframe of the licensed celltype in the plurality of cells.

At 1730, the wireless device may drop or scale at least one of the firstSRS or the second SRS based on a transmit power priority of the firstSRS and the second SRS when a calculated total power exceeds a firstvalue. The transmit power priority may consider whether the first SRS orthe second SRS is configured for transmission on the licensed cell typeor the unlicensed cell type. The first value may, for example, be amaximum allowed transmission power of the wireless device. The scalingof at least one of the first SRS or the second SRS may comprise,according to an embodiment, adjusting a transmit power of the at leastone of the first SRS or the second SRS and transmitting the at least oneof the first SRS or the second SRS in the subframe. The first SRS andthe second SRS may be configured for transmission in a last symbol ofthe subframe. The second calculated total power may be below the firstvalue when at least one of the first SRS or the second SRS is dropped orscaled.

The configuration parameters may comprise, for example, SRSconfiguration parameters. The SRS configuration parameters may comprisean SRS bandwidth parameter and an SRS subframe configuration parameter.According to an embodiment, the second SRS may be configured fortransmission in response to receiving downlink control information froma base station.

The wireless device may further transmit a second message to a basestation. The second message may comprise one or more second parameters.The one or more second parameters may, for example, indicate that thewireless device supports an enhanced SRS transmission procedure. The oneor more second parameters may, for example, indicate that the wirelessdevice supports configuration of an uplink for a cell of the unlicensedcell type. The wireless device may further transmit a transport block onat least one of the plurality of cells of the licensed cell type in thesubframe.

FIG. 18 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1810, a calculated total transmit power maybe determined for a plurality of signals. The plurality of signals maycomprise a first SRS and a second SRS. The first SRS may be configuredfor transmission in a subframe of a LAA cell type. The second SRS may beconfigured for transmission in the subframe of a licensed cell type.

At 1820, at least one of the first SRS or the second SRS may be droppedor scaled based on a transmit power priority of the first SRS and thesecond SRS when a calculated total power exceeds a first value. Thetransmit power priority may consider whether the first SRS or the secondSRS is configured for transmission on the licensed cell type or theunlicensed cell type.

In this specification, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” In this specification,the term “may” is to be interpreted as “may, for example.” In otherwords, the term “may” is indicative that the phrase following the term“may” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}.

In this specification, parameters (Information elements: IEs) maycomprise one or more objects, and each of those objects may comprise oneor more other objects. For example, if parameter (IE) N comprisesparameter (IE) M, and parameter (IE) M comprises parameter (IE) K, andparameter (IE) K comprises parameter (information element) J, then, forexample, N comprises K, and N comprises J. In an example embodiment,when one or more messages comprise a plurality of parameters, it impliesthat a parameter in the plurality of parameters is in at least one ofthe one or more messages, but does not have to be in each of the one ormore messages.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLabVIEWMathScript. Additionally, it may be possible to implement modulesusing physical hardware that incorporates discrete or programmableanalog, digital and/or quantum hardware. Examples of programmablehardware comprise: computers, microcontrollers, microprocessors,application-specific integrated circuits (ASICs); field programmablegate arrays (FPGAs); and complex programmable logic devices (CPLDs).Computers, microcontrollers and microprocessors are programmed usinglanguages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDsare often programmed using hardware description languages (HDL) such asVHSIC hardware description language (VHDL) or Verilog that configureconnections between internal hardware modules with lesser functionalityon a programmable device. Finally, it needs to be emphasized that theabove mentioned technologies are often used in combination to achievethe result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the presentembodiments should not be limited by any of the above describedexemplary embodiments. In particular, it should be noted that, forexample purposes, the above explanation has focused on the example(s)using FDD communication systems. However, one skilled in the art willrecognize that embodiments of the disclosure may also be implemented ina system comprising one or more TDD cells (e.g. frame structure 2 and/orframe structure 3-licensed assisted access). The disclosed methods andsystems may be implemented in wireless or wireline systems. The featuresof various embodiments presented in this disclosure may be combined. Oneor many features (method or system) of one embodiment may be implementedin other embodiments. Only a limited number of example combinations areshown to indicate to one skilled in the art the possibility of featuresthat may be combined in various embodiments to create enhancedtransmission and reception systems and methods.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112. Claims that do not expressly include the phrase “means for”or “step for” are not to be interpreted under 35 U.S.C. 112.

1. A method comprising: receiving, by a wireless device, at least one message comprising configuration parameters of a plurality of cells, the plurality of cells comprising at least two cell types, the two cell types comprising: a first cell type operating on a first frequency band; and a second cell type operating on a second frequency band; determining a calculated total transmit power for a plurality of signals comprising: a first sounding reference signal (SRS) configured for transmission in a subframe of the first cell type in the plurality of cells; and a second SRS configured for transmission in the subframe of the second cell type in the plurality of cells; and dropping or scaling at least one of the first SRS or the second SRS based on a transmit power priority of the first SRS and the second SRS when the calculated total power exceeds a first value; and wherein the transmit power priority is based on whether the first SRS or the second SRS is configured for transmission on the first frequency band or the second frequency band.
 2. The method of claim 1, wherein: the first cell type operates on the first frequency band based on a first radio access technology; and the second cell type operates on the second frequency band based on a second radio access technology.
 3. The method of claim 1, wherein: the first frequency band is a licensed frequency band; and the second frequency band is an unlicensed frequency band.
 4. The method of claim 1, wherein the first value is a maximum allowed transmission power of the wireless device.
 5. The method of claim 1, wherein: the first SRS is of a first SRS type; and the second SRS is of a second SRS type.
 6. The method of claim 1, further comprising transmitting to a base station a second message comprising one or more second parameters, the one or more second parameters indicating that the wireless device supports an enhanced SRS transmission procedure.
 7. The method of claim 1, further comprising transmitting to a base station a second message comprising one or more second parameters, the one or more second parameters indicating that the wireless device supports configuration of an uplink for a cell of an unlicensed cell type.
 8. The method of claim 1, wherein the scaling at least one of the first SRS or the second SRS comprises: adjusting a transmit power of the at least one of the first SRS or the second SRS; and transmitting the at least one of the first SRS or the second SRS in the subframe.
 9. The method of claim 1, wherein the configuration parameters comprises SRS configuration parameters, the SRS configuration parameters comprising an SRS bandwidth parameter and an SRS subframe configuration parameter.
 10. The method of claim 1, wherein the second SRS is configured for transmission in response to receiving downlink control information from a base station.
 11. The method of claim 1, further comprising transmitting a transport block on at least one of the plurality of cells of the licensed cell type in the subframe.
 12. The method of claim 1, wherein a second calculated total power is below the first value when at least one of the first SRS or the second SRS is dropped or scaled.
 13. The method of claim 1, wherein the first SRS and the second SRS are configured for transmission in a last symbol of the subframe.
 14. The method of claim 1, wherein the transmit power priority is further based on whether the first SRS or the second SRS is transmitted adjacent to a physical uplink shared channel (PUSCH) transport block.
 15. The method of claim 2, wherein: the first frequency band is a licensed frequency band; and the second frequency band is an unlicensed frequency band.
 16. The method of claim 2, wherein: the first SRS is of a first SRS type; and the second SRS is of a second SRS type.
 17. The method of claim 14, wherein: the first frequency band is a licensed frequency band; and the second frequency band is an unlicensed frequency band.
 18. The method of claim 14, wherein: the first SRS is of a first SRS type; and the second SRS is of a second SRS type.
 19. The method of claim 14, wherein: the first SRS is transmitted according to a first sounding procedure; and the second SRS is transmitted according to a second sounding procedure different from the first sounding procedure.
 20. The method of claim 1, wherein the calculated total transmit power comprises: a first transmit power of the first SRS; and a second transmit power of the second SRS. 